MINERAL® reference Ag/AgCl electrode
Description
Design: The main part of the electrode is a silver wire with silver chloride deposited on its surface. The Ag/AgCl wire is placed in a glass tube with a ceramic sintered end. In the upper part, the wire ends with a gold-plated electrical contact placed in a Teflon cap. This contact is used to connect the electrode to the apparatus using an alligator clip. The electrode key (glass tube) is filled with a 3 mol/l KCl solution. On request, the key can be filled with 3 mol/l NaCl solution. The length of the glass key may be adjusted to the user’s wishes. By default, it is 60 mm long. The electrode potential is +220mV relative to SHE (standard hydrogen electrode).
Filling silver chloride electrodes
The electrodes are delivered filled with electrolyte, i.e. a 3 mol/l KCl aqueous solution. They are ready to use. We deliver them in polypropylene tubes with cotton wool moistened with the same KCl solution. During transport and storage between measurements, the end of the sintered key is in contact with wet cotton wool immersed in it. If the solution leaks from the electrode, which rarely happens, it should be added using a micropipette. This is done as follows: Warm the Teflon cap with your fingers or briefly with a lighter, remove it, add the solution using a micropipette and push the cap with the Ag/AgCl electrode into place. In this operation, the solution from the electrode is partially pushed out by the sinter, so the solution must be shaken off so that the end of the key ending with the sinter is free from the solution. After a few minutes, air will be pushed out of the electrode (through the sinter), bubbles can be seen on the sinter. Then (after 2-3 minutes), turn the electrode over and shake it off so that the solution returns to its place and fills the electrode on the sintered side.
Preparation of electrolyte (3 mol/l KCl)
Dissolve 22.3 g of pure KCl in double-distilled water or water obtained by reverse osmosis and make up to 100 ml in a volumetric flask.
In case of any doubts, please contact us.
J. Golimowski
mineral@mineral.waw.pl
